1. Field of the Invention
The present invention relates to a technique that is usable when quantitative measurement of a biological sample is performed subsequently to screening by qualitative measurement of the sample.
2. Description of the Related Art
As conventional measurement of a biological sample, Japanese Patent Application Laid-open No. H06-102272 discloses an example of a measurement device that performs urine quantitative measurement subsequently to urine qualitative measurement. Japanese Patent Application Laid-open No. H06-102272 discloses the measurement device that automatically performs urinary sediment measurement or the urine quantitative measurement based on the result of the urine qualitative measurement.
In addition, Japanese Patent Application Laid-open No. 2014-20802 describes a measurement device that automatically performs re-measurement in the case where the result of the urine quantitative measurement exceeds a measurement range. The measurement device disclosed in Japanese Patent Application Laid-open No. 2014-20802 analyzes a urine sample diluted with a predetermined dilution factor in first analysis and, in the case where the measurement result does not fall within the measurement range, the measurement device further dilutes the urine sample used in the first analysis or uses an undiluted urine sample to perform second analysis. This operation is repeated a predetermined number of times until the result of the urine quantitative measurement falls within the measurement range. According to such a measurement device, it is possible to prevent an increase in required urine sample quantity. Note that the qualitative measurement is sometimes referred to as semi-quantitative measurement.
However, the above related art has had the following problems.
That is, the measurement device of Japanese Patent Application Laid-open No. H06-102272 does not disclose measures taken in the case where, depending on the urine sample, the measurement range is exceeded in the urine quantitative measurement and accurate measurement cannot be performed. In such a case, usually, it is necessary to dilute the urine sample and perform the quantitative examination again. Accordingly, there has been a problem that it takes a long time to obtain the measurement result of the urine quantitative measurement, and an additional reagent cost is required.
In the measurement device of Japanese Patent Application Laid-open No. 2014-20802, in the case where the result of the urine quantitative measurement exceeds the measurement range, the dilution factor of the urine sample is changed based on the measurement result of the first analysis. However, there is a measurement item of which the concentration cannot be determined from the measurement result of the first analysis. In such a case, it is necessary to perform the re-measurement a plurality of times. In this case as well, there has been a problem that, due to the repetition of the measurement, it takes a long time to obtain the measurement result of the urine quantitative measurement, and the additional reagent cost is required.
In addition, in antigen-antibody reaction as an example of the urine quantitative measurement, a phenomenon (prozone phenomenon) in which a measured absorbance is small in spite of an actual high concentration of a target component to be measured so that a calculated urine quantitative measurement value is smaller than its actual value can occur. It is well known that such a phenomenon occurs not only in the antigen-antibody reaction but also in other reactions (hereafter, the phenomenon is referred to as “a prozone-like phenomenon”). Similarly to the case where the measurement range is exceeded, the measurement device described in each of Japanese Patent Application Laid-open No. H06-102272 and Japanese Patent Application Laid-open No. 2014-20802 cannot efficiently solve the problem caused by the prozone-like phenomenon in the urine quantitative measurement. As the biological sample, blood, blood plasma, and blood serum are measured in addition to urine.